Apparatus for heating preforms made of thermoplastic material

ABSTRACT

An apparatus for heating preforms made of thermoplastic material includes a conveyance device for preforms having a longitudinal axis of extension intended to move the preforms along a predefined path. The apparatus further includes a heating component arranged along at least one portion of the predefined path. The heating component includes at least one heating element and at least one front reflective element, which are mutually opposite with respect to the predefined path in order to form between them a transit tunnel for the preforms. The heating element includes IR (Infra-Red) and/or NIR (Near-Infra-Red) lamps. The front reflective element includes at least one contoured plate-like body in order to form, in the direction of extension of the predefined path, an alternation of closer portions and spaced portions with respect to the predefined path that is extended substantially parallel to the axes of extension of the preforms.

TECHNICAL FIELD

The present disclosure relates to an apparatus for heating preforms made of thermoplastic material.

BACKGROUND

Preforms are constituted essentially by a tubular body which has, at a first end, a closed bottom and, at the opposite end, a neck that forms an opening: these preforms are usually intended for the manufacture of containers, such as for example plastic bottles, by blow molding said preforms within a mold.

Typically, the neck of the preform is separated from the remaining body of the preform by a so-called finish.

Before sending the preforms to the mold, there is a heating step so that the preforms, during the blow molding step inside the mold of the blow molding unit, are in a state of optimum viscosity.

For this reason, upstream of the blow molding unit there are ovens, typically of the tunnel type, designed to heat the preforms so that their body has a suitable temperature.

Usually, the oven is constituted by a plurality of modules, each of which is tunnel-shaped.

By way of example, in order to heat the preforms, apparatuses are currently used which comprise a conveyor that is designed to move, by means of a combined rotary and translational motion, the preforms along a preset path that passes through a plurality of tunnel-shaped modules.

The heating tunnels are constituted essentially by at least two side walls which are mutually opposite with respect to the path of the preforms and in particular by a first heating wall, which is associated with heating means designed to heat the preforms, and by a second reflective wall.

By way of example, the heating means can comprise incandescent lamps, infrared lamps, NIR lamps, which emit radiation in a specific region of the electromagnetic field (Near-Infra-Red).

A rather common drawback of known solutions resides in the low efficiency of the apparatus as a whole, which in practice forces the provision of extremely long heating tunnels or of a sequence of heating tunnels.

Moreover, in many cases it is necessary to provide means for cooling the lamps and the preform, which provide for forced ventilation devices adapted to introduce a flow of air that is transverse to the tunnel.

In this last case, the lateral surfaces of the tunnel have openings through which the air flow is to be introduced and aspirated.

As the openings provided in the heating and reflective walls increase, so does the ability to remove excess heat, but evidently the useful reflective surface is reduced, with a consequent decrease of the efficiency of the apparatus.

SUMMARY

The aim of the present disclosure is to provide an apparatus for heating preforms made of thermoplastic material that is capable of improving the background art in one or more of the aspects indicated above.

Within this aim, an object of the disclosure is to devise an apparatus for heating preforms made of thermoplastic material that is extremely efficient from the energy standpoint.

Another object of the disclosure is to provide an apparatus for heating preforms made of thermoplastic material that is extremely shorter than currently commercially available ones.

Another object of the disclosure is to provide an apparatus for heating preforms made of thermoplastic material that is highly reliable, relatively easy to provide and at competitive costs.

This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by an apparatus for heating preforms made of thermoplastic material according to claim 1, optionally provided with one or more of the characteristics of the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the disclosure will become better apparent from the description of some preferred but not exclusive embodiments of the apparatus for heating preforms made of thermoplastic material according to the disclosure, illustrated by way of nonlimiting example in the accompanying drawings, wherein:

FIG. 1 is a schematic top view of an apparatus 1 for heating preforms made of thermoplastic material according to the disclosure;

FIG. 2 is a front view of the rear reflective body;

FIGS. 3 and 4 are perspective rear views of two different embodiments of the front reflective element;

FIG. 5 is another perspective view of the front surface of a different embodiment of the rear reflective body;

FIG. 6 is another perspective view of the rear surface of the rear reflective body of FIG. 5;

FIG. 7 is a partially exploded perspective view of an embodiment of the heating element;

FIG. 8 is a sectional view of the heating element of FIG. 7, taken along a transverse plane;

FIG. 9 is a perspective view of an embodiment of the heating element; and

FIG. 10 is an exploded perspective view of the heating element shown in FIG. 9.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to the FIGS. 1-10, an apparatus for heating preforms made of thermoplastic material according to the disclosure, designated generally by the reference numeral 1, comprises a device 2 for the conveyance of preforms 10 which have a longitudinal axis of extension 100.

The conveyance device 2 is designed to move the preforms 10 along a predefined path 200.

Furthermore, the apparatus 1 has heating means 3 arranged along at least one part of the predefined path.

The heating means 3 comprise at least one heating element 4 and at least one front reflective element 5, which are mutually opposite with respect to the predefined path 200 in order to form between them a transit tunnel for the preforms 10.

The or each heating element 4 comprises a plurality of IR (Infra-Red) or NIR (Near-Infra-Red) radiation lamps 4 a.

The heating element 4 conveniently comprises a rear reflective body 4 b, which is arranged to the rear of the plurality of lamps 4 a with respect to the extension of the predefined path 200.

According to the disclosure, the front reflective element 5 comprises at least one plate-like body 6 which is contoured so as to define, in the direction of extension of the predefined path 200, an alternation of closer portions 6 a and spaced portions 6 b with respect to the predefined path 200 which is extended substantially parallel to the axes of extension 100 of the preforms 10.

In particular, the closer portions 6 a and the spaced portions 6 b are extended along the entire length of the preforms 10.

Conveniently, the closer portions 6 a and the spaced portions 6 b are formed on substantially planar surfaces.

According to a possible constructive variation, the plate-like body 6 comprises, between contiguous spaced portions 6 a and closer portions 6 b, respective linking parts 6 c.

Furthermore, at least one of the linking parts 6 c might be provided so as to form at least one transit opening 6 d for a cooling air flow.

Preferably, as shown in FIGS. 2 to 4, at least one closer portion 6 b has, at both of the parts 6 c for linking to a respective spaced portion 6 a, at least one transit opening 6 d for a cooling air flow.

According to a possible constructive variation, the front reflective element 5 can be provided by providing a first rear plate-like body and a second front plate-like body.

The second front plate-like body forms a plurality of slits which are parallel to the axis 100 of the preforms 10 and are alternated with closer portions formed on said second front plate-like body, so that the first rear plate-like body forms, at said slits, the spaced portions.

According to a possible constructive variation, the rear reflective body 4 b comprises at least one reflective contoured plate-like element in order to form an alternation of accommodation portions which have a concavity that is directed toward the predefined path 200 and are configured to arrange themselves at least partially around a respective lamp 4 a.

Furthermore, the accommodation portions can be formed by an alternation of closer portions and spaced portions with respect to the predefined path 200 which are extended substantially parallel to the axes of extension of said preforms.

Furthermore, the rear reflective body 4 b comprises at least one plate-like body 16 which is contoured to form, in the direction of extension of the predefined path 200, an alternation of closer portions 16 a and spaced portions 16 b with respect to the predefined path 200 which is extended substantially parallel to the axes of extension 100 of the preforms 10.

In particular, the closer portions 16 a and the spaced portions 16 b are extended along the entire length of the preforms 10.

Conveniently, the closer portions 16 a and the spaced portions 16 b are formed on substantially planar surfaces.

According to a possible constructive variation, the plate-like body 16 comprises, between contiguous spaced portions 16 a and closer portions 16 b, respective linking parts 16 c.

It is furthermore possible to provide for one of the linking parts 16 c to form at least one transit opening 16 d for a cooling air stream.

Conveniently, as shown in FIGS. 9 to 10, at least one closer portion 16 b has, at both parts 16 c for linking to a respective spaced portion 16 a, at least one transit opening 16 d for a cooling air stream.

According to a possible constructive variation, the rear reflective body 4 b comprises a first rear plate-like body 161 and a second front plate-like body 162.

The second front plate-like body 162 forms a plurality of slits which are parallel to the axis 100 of the preforms 10 and are alternated with closer portions 16 a formed on said second front plate-like body 162, so that the first rear plate-like body 161 forms, at said slits, the spaced portions 16 b.

It has been found experimentally that if the rear reflective body 4 b is also used, the heating of the preforms 10 is extremely more effective.

The radiation reflected by the front reflective element 5 that is not absorbed by the preforms 10 is in fact further reflected by the rear reflective body 4 b and so forth; the radiation further reflected by the rear reflective body 4 b that is not absorbed by the preforms 10 is further reflected by the front reflective element 5, in a synergistic process.

The shape of the rear reflective body 4 b can also be similar, i.e., can correspond to the shape of the front reflective element 5.

According to a particularly important aspect of the present disclosure, the or each contoured plate-like body 6, 16 is substantially made of metal.

Preferably, the or each reflective body is made of aluminum.

The use of the apparatus 1 according to the disclosure is as follows.

The preforms 10 are fed to the conveyance device 2 and along the conveyance device 2 they cross the transit tunnels formed by the heating means 3 constituted by the heating element 4 associated with the rear reflective body 4 b and by the front reflective elements 5.

In practice it has been found that the disclosure achieves the intended aim and objects, providing an apparatus 1 that has an extremely high performance.

In particular, tests have been conducted to determine the energy gain provided by using an apparatus 1 according to the disclosure with respect to standard apparatuses, both with metal components and ceramic components, of the type currently commercially available.

It has been found that by using the apparatuses according to the disclosure one obtains a reduction in length of even 10-30% of the transit tunnel and a substantially similar percentage reduction of electric power consumption.

Furthermore, it has been found that in some applications it is possible to lower, to the point of eliminating, the use of means for the ventilation and cooling of the lamps and of the preforms, with a consequent simplification of the apparatus as well as a reduction in overall costs.

The disclosure thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may furthermore be replaced with other technically equivalent elements.

In practice, the materials used, so long as they are compatible with the specific use as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.

The disclosures in Italian Patent Application No. 102017000007077 (UA2017A000368) from which this application claims priority are incorporated herein by reference. 

1-7. (canceled)
 8. An apparatus for heating preforms made of thermoplastic material, the apparatus comprises: a conveyance device for preforms having a longitudinal axis of extension, intended to move said preforms along a predefined path, and heating means arranged along at least one portion of said predefined path, said heating means comprising at least one heating element and at least one front reflective element, which are mutually opposite with respect to said predefined path in order to form between them a transit tunnel for said preforms, said heating element comprising a plurality of IR (Infra-Red) and/or NIR (Near-Infra-Red) lamps, said front reflective element comprising at least one contoured body in order to form, in the direction of extension of said predefined path, an alternation of closer portions and spaced portions with respect to said predefined path that is extended substantially parallel to the axes of extension of said preforms, wherein said closer portions and said spaced portions are formed on substantially planar surfaces, said contoured body comprising, between contiguous spaced portions and closer portions, respective connecting parts, at least one of said connecting parts forming at least one transit opening for a cooling air flow.
 9. The apparatus according to claim 8, wherein said closer portions and said spaced portions are extended along the entire length of said preforms.
 10. The apparatus according to claim 8, wherein said heating element comprises at least one rear reflective body.
 11. The apparatus according to claim 10, wherein said rear reflective body comprises a reflective contoured element in order to form an alternation of accommodation portions which have a concavity directed toward said predefined path and are configured to arrange themselves at least partially around a respective lamp.
 12. The apparatus according to claim 11, wherein said accommodation portions are formed by an alternation of closer portions and spaced portions with respect to said predefined path that is extended substantially parallel to the axes of extension of said preforms.
 13. The apparatus according to claim 10, wherein said rear reflective body comprises at least one body that is contoured to form, in a direction of extension of said predefined path, an alternation of closer portions and spaced portions with respect to said predefined path which is extended substantially parallel to the axes of extension of said preforms.
 14. The apparatus according to claim 13, wherein said contoured body is substantially made of metal. 